CBS News senior global affairs contributor and Eurasia Group president Ian Bremmer said Mr. Trump deserves credit for getting Kim to a point where he's apparently willing to discuss denuclearization, yet he warned that the outcome of talks is far from certain. In the past, he noted, "the process once the North Koreans said, 'Hey, we're willing to do this stuff,' has been abysmal."

On "CBS This Morning" Monday, Bremmer called it "a really big deal" that Mr. Trump agreed to meet with the North Korean leader; he would be the first American president or world leader to do so. But there could be downsides.

"He's made a big give to the North Koreans by saying, 'I'm going to legitimize you. I'm going to meet.' He doesn't think he's given anything, but he doesn't know anything about this policy. We know, we've already seen it with tariffs, Trump's ability to make big statements because he doesn't understand details of the policy and then people have to walk it back that actually implement, is overwhelming. And on North Korea, that's dangerous," Bremmer said.

"The reason why [former Presidents] Obama, Bush, Clinton haven't met with North Korean leaders is because they understand that dealing with what is already a nuclear power, a rogue state, no information, incredibly intractable, things can go really badly," Bremmer said. "If you offer a head-of-state meeting, you make your presidency about North Korea, which is – that and Israel-Palestine, like the hardest things to try to unwind. Presidencies can go south on that sort of issue."

Bremmer said when the South Koreans briefed the president about their meeting with Kim last week, "They were not suggesting, 'Hey, go and meet with him right away.'"

"They're actually concerned," he said.

He also pointed out that U.S. Secretary of State Rex Tillerson was out of the loop on this crucial decision. "Secretary of state had no idea – literally had no idea. That's thoroughly unprecedented," Bremmer said.

The Japanese, whom Bremmer called "our best allies," thought the Trump administration was taking a hard-line stance on North Korea, but "suddenly the Japanese [are] completely blindsided by Trump accepting a meeting."

"You want to have your allies onboard. That means the Japanese and the South Koreans. You also want your allies inside the administration onboard and Trump – a good job getting to this point, an abysmal job because he's going it alone," Bremmer said. "You need to have the people around you that can help get to a better place. I hope that changes in the next 72 hours."

White House spokesman Raj Shah said no location has been determined for the talks, but it's unlikely Mr. Trump will go to North Korea.